The Backup Blog

VTL: What Matters?

As a result of some of the longish posts, comments, and replies about the architecture and functionality of DL4000s with deduplication that I engaged in with Curtis Preston and others, I got to thinking.

My feeling was that Curtis was wrong, but not for any specific technical reason.

Sure, some of his points were wrong in my estimation. Some were right.

But even accounting for that, I had the feeling that the sum of his argument was more wrong than right, and more wrong than I could account for by simply saying that this or that specific point was wrong.

Put another way: the whole of his argument was less than the sum of its parts.

But why exactly he was wrong is, I think, interesting.

Mr. Preston is wrong because the discussion is not relevant. Not cogent to why somebody might choose to buy a particular virtual tape library, or deduplication device. So ultimately, it comes down to not so much that he is wrong, but that the whole discussion fundamentally misses the point, and is not relevant.

It doesn't pass the "so what?" test.

Mozy and Restore

On a scale of personal data disasters from 1 to 10, what would you rate a simultaneous double disk failure of your RAID 1 group and a more or less complete corruption of your Time Machine backup images? Pretty high I would guess. Let's call it a 8.5. The only real way it gets worse is if you simultaneously lose root.

Fortunately, I have Mozy.

(I also have a sparse bundle of backup data that I can open and read, but I can't copy files from it without getting error messages. I welcome any thoughts any of you might have on that one!)

Before I initiated a restore with Mozy I did a quick google around to see what sort of restore speeds I could expect. To my surprise, the first few responses google returned didn't leave me with much optimism.

However, not only did I not have much optimism, I also didn't have much choice. So I gritted my teeth and got down to it.

The good news (and really the only good news of the day) is that Mozy is happily restoring my data at pretty reasonable speeds: peaking at over 2.0 MB/s over my ISP connection, and averaging somewhere around 1.0 MB/s. And it was ridiculously easy to browse the data that I wanted to restore, pick a destination, and just restore. I was at about 35 GB restored when I left for work this morning, with no hiccups, burps, or other forms of nastiness from Mozy.

It is just working, and working well.

Which is really the whole point. Mozy, not just for backup, but restore too!

EMC and Quantum Strengthen Relationship

EMC and Quantum announced today that they were strengthening their relationship as EMC loaned Quantum $100m to refinance debt.

The significant thing about this is, to my mind, that it is a loan. Not a purchase of stock, not a take over or partial take over or any such thing. It is a loan, made to a partner that supplies EMC with some very important technology: deduplication software for backup.

The other important aspect of this is that it comes on the heels of a very successful quarter for Quantum; the EMC loan is a clear reflection of the confidence we have in the company and their technology. For Quantum, this allows them to focus on their technology, and growing their business.

The market seems to have reacted positively, as QTM is up 90% as of the time of this writing.

Does Global Deduplication Matter?

Curtis Preston penned something last week asking if global deduplication matters. I am not sure if Curtis would count me in the group that questions global deduplication's reality, or not...

Of course I believe it is real!

The real issues are actually two-fold: does it matter, and if so, how much?

Mr. Preston claims that it only matters if you back up more than 10-20 TB. Well, that is a pretty broad range. I would actually amend this to a more specific number: for a single EMC DL3000 that is 18 TB (12 hours of deduplication), and for a DL4000 with deduplication enabled it is 30 TB. Why the larger number? Because with deferred deduplication and faster ingest speeds, it is perfectly legitimate to deduplicate throughout the day. For the sake of operational realities, I am assuming you are deduplicating for 20 hours with this number. That still leaves ample time for other niceties, like restore, for example.

The Backup Blog is on Vacation

Just a note to all that I will be on vacation until March 16. During this time I will be unable to moderate and post comments, and unable to respond to comments as well. So you will just have to hold your fire until I am back!

While I am gone, I will be riding my bicycle up this:

It doesn't look like 10,000 feet of up from that perspective, does it?

Web Demos of EMC Backup, Recovery, and Archive Products

For a while now the good folks at Avamar have been offering once a week demonstrations of the product via webex. The schedule has now expanded to include some of the other products in our backup, recovery, and archiving solution set.

The schedule is now as follows:

Times	Monday	Tuesday	Wednesday	Thursday	Friday
8:00 –9:30 am (pacific)	HomeBase (bare metal recovery)	EmailXtender (email archiving)	NetWorker (backup and recovery)	RepliStor (remote file replication)	Avamvar (source based dedup)
10:00-11:30 (pacific)				Data Protection Advisor (backup reporting and analysis)

Complete URLs, dial-in numbers, and product details can be found below. You can also find longer descriptions and product links below.

DL3D Adds OST Support

This one sort of snuck out the door: with the latest version of the DL3D code, EMC has added support for Symantec's OST initiative.

OST is a way for Symantec NetBackup to address "disk as disk" rather than as virtual tape. More important than this, in my mind, is the ability of an OST enabled device to replicate in a much more intelligent way, and in a way that tightly integrates with the backup application.

What do you need from Symantec? Well you need NetBackup v6.5. And you need the OST plug-in installed on any media server that is going to connect to the DL3D. Connection over IP (only) is supported. And in Symantec's parlance, the DL3D becomes a "storage server".

This storage server contains Logical Storage Units which are available to Media Servers. The Media Servers then access the pool of deduplicated storage on the DL3D as they would any other NFS or CIFS attached storage.

Why Do We Build A DL4000 3D?

I have had a lot of comments, mostly constructive, on some of posts about performance and the EDL 4000 3D. (The translation of that product name, by the way, is the EMC Disk Library 4000 with deduplication.) W. Curtis Preston has been one of the most vocal critics, and while I think he is dead wrong--nothing personal, Curtis, that is just my opinion of your opinion--I don't think his comments are so trivial that I am going to dismiss them out of hand. I also suspect that they are roughly congruent with the initial reaction some users might have to the device.

So I wanted to take the opportunity to address some of these comments in a more structured fashion than just the back-and-forth in the comments section. Giving Mr. Preston his due, I will quote him directly and then respond to the objections.

NetWorker Goes Virtual

One of the things I personally appreciate most about VMware is just how easy it is to download different applications and keep them around in an inactive state until I need them to answer a customer's question or one of my own. How does feature "x" work? Various groups within EMC have embraced this capability to make machine, appliance, or application services available within a VM: Avamar and Celerra, for example, both have VM versions. Now the NetWorker folks have released a NetWorker server VM too. You can get it here: http://www.vmware.com/appliances/directory/69672. And for a short write up with some good hints on getting it going, look no further than the man with the razor wit, Storagezilla, in his post here.